is a tumor of the pineal gland
The pineal gland produces the hormone melatonin
which plays a role in regulating circadian rhythms
. A pinealoma may disrupt production of this hormone, and insomnia
Frequently, paralysis of upward gaze along with several ocular findings known collectively as Parinaud's syndrome are the only physical symptoms seen. This is caused by the compression of the vertical gaze center in the midbrain tectum at the level of the superior colliculus and cranial nerve III. Patients may also present with pupillary disturbances and eyelid retraction (Collier's sign).
A pinealoma may cause interruption of hypothalamic inhibiting pathways, sometimes leading to beta-hCG secretion and consequent Leydig's cell stimulation.
Other symptoms may include hydrocephalus, gait disturbances, and precocious puberty.
Pinealomas can be due to proliferation of primary pineocytes
(pineocytomas, pineoblastomas), astrocytes
), or germ cells
). Germinomas are the most common tumor in the pineal gland.
Of the different types of pinealomas, the type with the most favorable prognosis is the pineocytoma.